Conveyer drive control



Sept. 2, 1952 F. A. T ERHUNE 2,609,085

' CONVEYER DRIVE CONTROL Filed Aug. 7, 1948 2 SHEETSSHEET l Zhwentor v z 2% 421M? an I l A, I 6/ zi. ja I (Iorcgs Sept. 2, 1952 i A, TERHUNE 2,609,085

CONVEYER DRIVE CONTROL F'iled Aug. 7, 1948 2 SHEETSSHEET 2 (Itlornegs Patented Sept. 2, 1952 UNITED PATENT" OFFICE CONVEY'E'R; DRIVE CGNTROL Etan A,- ,1e h n l i 1 Mass ss gn to; G n:

qrazlMq ors C rpora o Dctroit Mic hi-l 8; Q?

Apbliea'tion; August-7, 1948; Serial No; 43,081 901 mm (C 1.9 20

"'E is; in e tion r atea: tqon yors. for 2h ample Qh n qqn exdrsi nd; art ularly omeans. g-a fi omz n e nv p -dr e units .9 meenda hahmeyqre break-d wn? nd medamz q regu ing: t em rQme m nafi least subst tia l ce l-l Altbqu h. applicable Am broade t sense. o q y q a; ri e a sin l drive unit, the. in! ventiqnw y; concern w th centrolling plum k tofun fl te 'al spa e rp in s al n aq nveyorw in a -m nn w ic wi l k ep h mv synqhmn zficland p en emes iy slaqkr-qqw n iin. hecon y rr ne-be w en any hwq drlv Msochtedwith ch; dr ve' n qQntroL deviqe for: sto pin the n afiion. he eo a d actua able. by embe mq bly tesnqm v 0 tha v lwment-o slack in h enm yor ne -beiaween ha drive ni an he dr yeumta eadr The-principal object Qfitbe inyentio is tame: i e ans e ponsiv e o nc urrence-qf 6X96 s e eqsla r nveyon ine tw en suqses ve dxim-uniztsr hereqn't r. synqhmn zin aid dxi eu t' ia dih ereby co trol ing he; deve opment QisSfildSlfiQk- 1 Another qbje h qi he nva t en :is; p qvide. m ana 0 7. ut matical y; st p ng one f, p111 mli y of; qonv m? drivei ni s. when ex s ive la k lev l m. n. neq nveyqr line; betwee that and an a ija cqnt, fllunit," but wh ch; u on said slaakwbe n taken? I will alIQw said first; mentiIQnQdj'dn-iveunit tqir'es me operat on,

Ai otfie' Qbjectof th e inveniz on i to. n oYi ontr l for syn h .nizinganl raHfix 0i riveg ni siai iat d with; Qo ye or. line uch;

demons i he. 9% 1t tin e'to ,fijin .Hfiifi s 'islaq s ha be aken up and said r arm t drweunit peration;

'Themanne y'whicnthes an Qt qb ec s 841:6 afltained 'by the'invention willjbe readily ap gam t from: the te w g scrip n sm conneotigmwith the drawin s illustrating agrefeiz red structural embgdiment thereof," and in wh c Figure 1*is" ax planvi'ew ofaJportion-nf anonveyer line and one of" itsdriving 1 units, with an atfiaehmenfifermmg "parto? my inventibn installed thereon and shwn "in its ndrmal -position. 'l figure la is a.partlyldiagrammatic'view'similar foomum 1 shbw'ing the arrngement of the com anel-extead nga am lel th ww th e upw 2 v veyq line-With two dfi fis mi d 12@ ion therea qn h a n o whi h as as: d witrkitap atteqh mm awo am thm vention,

Eigwse 2 1% w ew m a Eiswe 1 uilhf nerspecg .hqw n-. Q)? he w eyer ine ment n he. e. I Ei weh an i; tan inhrcke ine bwtx I f: Qer aix l n m 9 he, a ta hm m i t. q ens igure e Qir uit-diagmm 1lQ i a" a rang m m of th eleq r calf ah 2 qmlo rd #2 carryin wh m w nt j CQIWWQIFHEE nav n q dlrive m Shown in Figur s ,19; o fthe raw qqx veyenline 20 onvent qn l @hai 16 sis ing fli m and cqup in 'fi pivqt l 91 t ge her by tica ns 8; and sli iab y Sii' 11 s atmn r ra eways. ormd y" obi Isr a utward y Own? ha n memb'i an l res n Qh-a. ur rtiii l conveyor i 2/ films; b i ix' uduslo b a riven. at sp c d st n's: the ealq i iz r me rs. q q h now mean (n' tshwi ae n e o d e ha n 0 hich my b, s; in} con sftxfuqtionthe cqnveybfline] Z ieiicb't mq id d h o wardl e d ng 111,38 2 a ed: tq engag hecqr vfiyop 1111? b me be wg n he u li fi 6'- her fe qh i h gonvelm? driv chair; 2 h? e q er: me s; m un e n ertical 3 .3% w h guid i mm n ag m ny with the lu s .2- .k the base n qbside 9? e eQn re q 12 11. qhan glwt ifi. ea t-0. tra ss; er-- he shgwn),

ln-ethe-aemngemem w wn th nqme g elineq t iwel=- i he q rwt gn i the anew 21 slifitingui hfidi m me usual qpns r tle A n he CQIWQYQIPLIQQ n wme sa rww 1. 1 11 l avi the dlriv @hain' 2mm, tion qqntempl ew qv dm ap in a this m nd; iwxtm merem: anew meat emnmme nlq able I mcew y ind exwrally by r 2119 numfim 3!!" whiqh; is; p abgut ni-M m l da lm sup o ted n lafie i fi ed tq n base 5: The movab e; M may as, mawnxheg cmvani nt y eonstmczted 2 a5 Walsh as EQIEVQWF ru k (@912 of a plate 34 having an up-turned edge 35 one end 38 of which is flared outwardly as shown to form an entering guide for one side of the conveyor line 2, and an outwardly open channel section 40 welded thereto and having its end 4| flared outwardly in the opposite direction to form an entering guide for the other side of the conveyor line. Also fixedly attached to the plate 34 as by welding, and extending preferably parallel with the normal direction of movement of the conveyor line, is an arm 42 to which is attached one end of a flexible member such as the cable 43 extending transversely therefrom and running over a sheave or pulley 44 supported by the base l5. The other end of the cable is attached to a biasing means such as the weight 46 which is continuously suspended therefrom and tends to rotate the movable raceway 30 about its pivot pin 3| from the position shown in Figure 1 to that shown in Figure 2. Fixedly attached to the arm 42 for movement with the movable raceway 30 is a'trip member or dog 45 adapted to engage the actuating lever of a normally closed electrical switch 48 fixedly mounted on the base [5.

It will be noted that the stationary channel section [3 extends a substantial distance closer to the drive chain 20 than the adjacent end of its cooperating stationary channel section l2, and that the movable channel section 40 extends approximately the same distance in the opposite direction beyond the movable plate 34 to the pivot pin 3!. Also, the movable plate 34 with its upturned edge 36 extends substantially closer to the drive chain 20 than does the movable channel section 40. With this arrangement the stationary channel section I3 serves as a stop for the movable raceway 30 as it returns from its position shown in Figure 2 to its position shown in Figure 1. In addition, by reason of the conveyor line 2 being laterally unrestrained over a substantially longer distance on the side nearest the castor track 25 than on the opposite side, as slack develops in the line 2 after leaving the drive chain 20 it will tend to bow or buckle in that rather than in the opposite direction. The weight 46 is chosen of sufficient magnitude to overcome the sliding friction between the movable plate 34 and the stationary wear plate 32, and to maintain the plate 34 in contact with the conveyor line 2 as the latter buckles with excessive slack. In addition, as tension decreases in the conveyor line 2 toward a slack condition, the weight 45 will tend to assist the buckling of the line 2 in the direction toward the castor track 25.

As is apparent from the description heretofore given, with the conveyor line 2 in normal operation, the movable raceway 30 is held thereby in the position shown in Figure 1. Upon the occurrence of excessive slack developing in the 'conveyor line 2 between its leaving the drive chain 20 and its entrance into the stationary raceway provided by the stationary channel sections I 2 and I3, due either to a break occurring in the line 2, a failure of the drive unit ahead, or the line 2 jumping out of its raceway at a turn, etc. the weight 45 will tend to cause the movable raceway 30 to pivot to the position shown in Figure 2, during which movement the trip dog 45 will actuate the switch 48 to open position.

' It is contemplated that an attachment will be employed in the manner described adjacent each driving unit, as indicated in Figure la. In Figure 4 is shown a diagram of the electrical control circuit for a conveyor line driven by two drive units, the circuit elements associated respectively 4 therewith being designated with numerals prefixed by A and B. The electric motors or other means for operating the drive units are controlled by magnetic contactors or relay switches, the windings A-50 and 13-50 of which are shown. Current is supplied from a suitable source through leads 52 and 53, between which under normal operating conditions current flows through two parallel circuits A-54 and B-54 which include respectively the windings A-5U in series with the normally closed slack responsive switch A-43 and the winding 3-50 in series with the normally closed slack responsive switch B-48. Linked to close upon opening of the normally closed slack responsive switches A-48 and B-48 respectively are normally open switches A-55 and 3-55 in parallel between a common conductor 56 connected to the lead 52 and a common conductor 5'! connected to the lead 53. In series with the normally open switch A-55 and between it and the common conductor 5'l are a relay coil A-58 and a normally closed manually actuatable resetting switch A-59. Similarly, between the normally open switch B-55 and the common conductor 51 are a relay coil 13-58 and a normally closed manually actuatable resetting switch B-59. Biased to its open position as shown and closable upon energization of the relay coil A-58 is a double-armed switch A-Bfl, the arms A-BI and A-BZ of which are adapted when moved to their closed positions to complete a holding circuit for the relay coil A-58 between the common conductors 56 and 51, and to complete an energizing circuit between the same conductors for a signal device such'as the pilot lamp A-63.' Similarly associated with the relay coil B-58 is a pilot lamp B-53 and a double-armed switch B-BO having arms B-Bl and 3-62. There are also preferably provided normally closed manually actuatable start-stop switches A-64, B-64 and normally closed over-load actuated switches A-65, 3-65 for the two drive units, all four of such switches being in series with both the normally closed parallel circuits A-54 and 3-54. Linked to close upon opening of the switches A-64, 3-64, A-65, B-65 respectively are normally open switches A-66, B-66, A-fil, B-ST, which are adapted in their closed positions to complete energizing circuits for the pilot lamps A-68, B-BB, A-69, 3-59 between the common conductors 56 and 51. In operation, in event successive slackdevelops in the section of the conveyor line moving from drive unit A to an adjacent drive unit B (the latter being considered the more forwardly in the direction of motion of the conveyor line), the normally closed slack responsive switch A-48 will open, which will cause the winding A-50 to de-ener'gize, stopping the drive unit A. Also,the opening of switch A-48 e'ffectsfl'a. simultaneous closing of the normally open'switch A-55 linked thereto, and an energization of the relay coil A-58 which causes the normally open double armed switch A-GU to close, holding the relay coil A-58 and pilot lamp A-63 energized. 'Should the excess slack in that section of the conveyor line be subsequently taken up, as for exampleby the continued operation of drive unit B, the slack responsive switch A-48 will return to its normally closed position, re-energizing the winding 4-50 to restart drive unit A.. As a signal to identify the section of the conveyor line wherein the excessive slack conditionhad developed, however, the pilot lamp A-63 will continue to glow until the circuit through the relay coil A-58 isnbroken i d to-lignt u V similarly'g in thelevent -excessiva: slackdevelops in the section er ithe :conveyorain between the and the next drive iinit ahead in, in o. two-or e unit (inves ors-system)-gistnenew mally 'closed' slack respoiisive switch n -:48 opens, stoppingdrive -unit-B while the nextwdrive iimt lamp "B 53. "Actuation or anyone :ot' the manualii'or over load switches -A-l-filj 13-64; A 'flp-Betix fromtheir aliead continues to: operate; and ilighting "pilot normally closed positiona causes botli drive-iinits movable racewaysand thesdriving ilnits, each of the stationary raceways comprising oppositely disposed parallel guide members having their end adjacent the movable raceway --fmembers in staggered complementary"relation therewith. each or the movable raceways being pivotable about the end thereof most remote from its adjacent driving unit'in response to excessive slack occurring in the section of the conveyor line embraced thereby, switch means for controlling each drive unit independently and actuatable by pivotal movement oi the movable raceway adjacent thereto.

2. In a conveyor system, a conveyor line driven by a plurality of spaced and separately controllable drive units, stationary raceways between successive drive units comprising cooperating parallel guide members embracing the conveyor line, one of the guide members of each stationary raceway having one of its ends more remote from the adjacent drive unit than the corresponding end of its cooperating guide member, a movable raceway between the said ends of each -stationary raceway and the adjacent drive unit,

each of the movable raceways comprising two relatively fixed parallel members embracing the conveyor line in normally substantial continuity with the guide members of stationary raceway adjacentthereto, each of the movable raceways being 'pivotableabout ,a point adjacent the end of the more remote ended guide member of the stationary raceway adjacent theretovln response to slack occurring in the conveyor line between the drive unit adjacent thereto and the next drive unit ahead, control devices for controlling the operation of each drive unit independently, said control devices being mounted adjacent their respective drive units and adapted to be actuated by the movable raceways in pivoting from their normal positions.

3. In a conveyor system; a conveyor line having flexibility in one principal plane; a plurality of conveyor driving units engaging the conveyor line at spaced stations therealong; raceways ernbracing the conveyor line between successive driving units, each including a portion movable in said principal plane of flexibility in response to excessive slack occurring in the conveyor line;

relay switches for independently controlling the operation of the respective drive units; electrical circuits for energizing the relays and there- Means:

b' niandaiiy- -opening the iici niallyi blosetlasset ting swit'ehA-fl; m

by 'rn'ain'taining the respective drive snnitsvin goperation; normailytclosedi-switches ineachxorisaid circuitsiin series with the. erelaywtherein, ;said normally closedswitches being actuatable-tozonon pesitionbythe-movable portions .of itheiraceways.

feach end thereof; and deviees responsivetOeDiW otal movements of each respe'ctive chaineguided raceway'ior controlling Ethe zoperation of 'atlie driving chain adjacent thereto.

' 5. In a conveyorsystem aeontinuous'conyeyor line driven byflrivin members spac dlydisposed therealong, stationary raceways forguidin the conveyor ilinebetween successive drivingmeness r Each of lih f t ql-fl y I lQQWl QQmDIi* ing two parallel guide membemembiacingthe conveyor line and terminatin at sta ered di tances from the driving member adjacent one end thereof, a movable raceway between the staggered ends of each stationary raceway and the driving unit adjacent thereto and comprising generally parallel relatively fixed members embracing the conveyor line, one of said members of each movable raceway being adapted in its normal position to eiiect a continuation of the guide member terminating nearest the adjacent driving member, the other of said members of each movable raceway being pivoted at its end most remote from the driving member adjacent thereto for free swinging movement away from the guide member terminating nearest said driving member in response to excessive slack conditions occurring in the conveyor line, and a switch opposite the swinging end of each movable raceway and operable upon outward movement thereof to stop the driving member adjacent thereto.

6. A control system for a conveyor line driven b a plurality of drive units, comprising relay switches controlling the operation of each drive unit independently, a current source for energizing the windings of said relay switches, parallel circuits for connecting said windings to the current source and including normally closed switches in series therewith, members disposed respectively between each pair of successive drive units and movable relative thereto in response to the degree of slack occurring in the conveyor line therebetween, extreme movement of each said member during increasing slack being effective to open the switch in the circuit of the winding of the relay switch controlling the drive unit rearwardly adjacent said member, normally open switches closable respectively upon opening of said normally closed switches, other relay switches closable respectively in response to closing said normally open switches and provided with holding circuits operative to maintain them in closed positions after their initial closure, signal means associated with each drive unit and operatively subject to the closing of said last named relay switches.

7 1'7. in aconvyorisystem, a conveyor'line.hav-' ing a plurality of driving members engaging the same at spaced stations therealong, stationary racewaysifor guiding the line between'successive stations a line guided raceway normally positioned between one end of each stationary raceway and thelstation adjacent thereto, said stationary and guided raceways having complementary adjacent end portions embracing the conveyor line each of the line guided ra'ceways being movable from its normal position in response to slack occurring in the line between the driving members nearest each end thereof, and devices responsive to the movements of each respective'line guided raceway for controlling the operation of the driving unit adjacent thereto. 8. In combinationwith a conveyor line driven by a plurality of separately controllable driving units 'at spaced stations therealong, a raceway for'the conveyor line between each pair 'of successive driving units including a portion movable in response to slack developing in the conveyor line, said raceway and its movable portion having their adjacent ends in complementary embracing relation with the conveyor line,

and devices responsive to movements of said portions for controlling the operation of the respective driving units.

- 9. A control system for a conveyor line driven by a, plurality of drive. ,units, comprising relay switches controlling the operation; of the1respe cjtive-tdrive units independently. a current,source for energizing the windings of said relay switches, parallel circuits connecting; said windingsto the current source, each saidcircuit including a normally closed switch in series with its relay winding arranged to open in response to excessive slack occurring in the conveyor line between the drive unit associated therewith and the next drive unit ahead, normally open switches closable respectively upon opening of said normally closed switches, other relay switches closable respectively in response to closing said normallyv open switches and provided with holding circuits operative to maintain them in closed positions after their initial closure, signal means associated with each-drive unit and operatively subject to the closing of, said last named, relay switches "FRANKATERHUNE,

REFERENCES CITED H v The following references are of record in the file of this patent:

UNITED S'I A'IE S PATENTS Date Number V Name I 1,370,029 Macderrnid Mar. 1, 1921 1,620,532 Fisher Mar. 8, 1927 2,472,526 Frazee June 7,1947 

